Stability analysis and deformation control method of swelling soft rock roadway adjacent to chambers

The surrounding rock of swelling soft rock roadway has high clay mineral content, strong expansibility after encountering water, low strength and poor cementation. The roadway is prone to large deformation under the influence of complex geostress. Combined with the support change of the development roadway of 2# coal in Hongqingliang mine, through geological survey, field observation and indoor test, the failure mechanism of the traditional support method of anchor bolt + anchor cable + anchor mesh + shotcrete was revealed by the adjustment of the surrounding rock stress after the excavation and support of the adjacent chambers. The research results show that the surrounding rock stress will cross the adjacent chambers and form a concentrated area near the weakly cemented roadway, and the maximum stress increase ratio of surrounding rock within the stress concentration range will reach 50%. The farther the chambers are from the weakly cemented roadway, the smaller the range of the surrounding rock stress concentration area. When the distance exceeds about 12 times the average height of the chambers, the surrounding rock stress concentration tends to disappear. Based on the fully enclosed combined support method of the U-shaped steel sheds closure roof and sides + filling flexible material behind the sheds + laying reinforcement mesh and concrete in floor + strengthening key parts, the construction process flow applicable to the working condition of swelling soft rock roadway is formulated.

Automated summary

The failure mechanism of the traditional support method for the swelling soft rock roadway was revealed through geological survey, field observation, and indoor test. The research found that the surrounding rock stress will concentrate near the weakly cemented roadway, with a maximum stress increase ratio of 50% within the concentration range. The study also developed a construction process flow for the fully enclosed combined support method suitable for the working condition of swelling soft rock roadway.